High-resolution photosensitive resin composition usable with i-line and method of forming pattern

ABSTRACT

A radiation sensitive resin composition for i-line light exposure comprising an alkaline soluble resin and a quinonediazide group-containing photosensitizer where said alkaline soluble resin comprises a novolak resin and a mixture of one or two or more of resins selected from the group of (i) polyacrylate, (ii) polymethacrylate, (iii) a polystyrene derivative and (iv) a copolymer consisting of two or more of monomer units selected from the group of acrylic ester, methacrylic ester and styrene derivatives is applied on a substrate such as a substrate for a flat panel display and exposed preferably at the light-exposure quantity of 50 to 500 mJ/cm 2  by an i-line light exposure source to form a pattern with high-resolution and a good pattern shape having no tailing.

TECHNICAL FIELD

This invention relates to a pattern forming method by i-line lightexposure and a radiation sensitive resin composition used therefor whichis suitable for a manufacturing of semiconductor devise, flat paneldisplay (FPD), etc.

BACKGROUND ART

In the wide field of manufacturing semiconductor integrated circuitssuch as LSI, producing a display surface of FPD, manufacturing a circuitsubstrate for thermal head etc., and like use, photolithographytechnique has so far been employed for forming microelements orconducting fine processing. In the photolithography technique, apositive or negative-working radiation sensitive resin composition isused for forming a resist pattern. Of these radiation sensitive resincompositions, those compositions comprising an alkali-soluble resin anda photosensitizer of quinonediazide compound are popularly used as thepositive-working radiation sensitive resin compositions. As suchcompositions, there are described compositions having differentformulations as, for example, ‘novolak resin/quinonediazide compound’ inmany documents such as Japanese Examined Patent Publication No.documents such as Japanese Examined Patent Publication No. S54-23570(U.S. Pat. No. 3,666,473), Japanese Examined Patent Publication No.S56-30850 (U.S. Pat. No. 4,115,128), Japanese Unexamined PatentPublication Nos. S55-73045 and S61-205933, etc.

These compositions comprising a novolak resin and a quinonediazidecompound have so far been studied and developed with respect to bothnovolak resins and radiation sensitive materials. In respect of novolakresins, there have been developed novel resins. In addition, radiationsensitive resin compositions having excellent properties have also beenobtained by improving physical properties of conventionally knownresins. For example, there are disclosed techniques providing aradiation sensitive resin composition having excellent properties byusing a novolak resin with a particular molecular weight distribution inJapanese Unexamined Patent Publication Nos. S60-140235 and H01-105243and by using a novolak resin from which low-molecular-weight componentsof the resin has been removed by fractionation in Japanese UnexaminedPatent Publication Nos. S60-97347, S60-189739 and Japanese PatentPublication No.2590342.

On the other hand, degree of integration in semiconductor elements havebeen increased year by year and, in the manufacture of semiconductorelements or the like, processing of patterns with a line width of lessthan sub-micron order has become required. However, conventionally knownradiation sensitive resin compositions can not satisfy enough theserequirements in the prior art described above. Furthermore uponmanufacturing a display surface of liquid crystal display (LCD) etc.,the exposure by using exposure apparatus with g-line or g+h-lineradiation source has been being conducted so far, however it has begunto examine a manufacturing process using i-line radiation source forforming a fine element and the radiation sensitive resin compositionhaving high resolution suitable for i-line light exposure.

In order to realize the high resolving ability of a radiation sensitiveresin composition for i-line light exposure, a technique to apply1,2-naphthoquinone-2-diazide-5-sulfonic acid ester of1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)butane as a photosensitizer(Japanese Unexamined Patent Publication No. H06-332167), a technique toapply novolak resin derived from the particular phenolic compounds andphotosensitizer (Japanese Unexamined Patent Publication Nos. H05-88364,H10-20503, and 2000-137324), a technique to apply photosensitivecomponents containing naphthoquinonediazide sulfonic acid ester oftrihydroxybenzophenone and trihydroxybenzophenone at the particularratio (Japanese Unexamined Patent Publication No. H08-82926), atechnique to apply an admixture of1,2-naphthoquinone-2-diazide-5-sulfonic acid ester of2,3,4-trihydroxybenzophenone with the particular esterification ratioand 1,2-naphthoquinone-2-diazide-5-sulfonic acid ester of2,3,4,4′-tetrahydroxybenzophenone as a photosensitizer (JapaneseUnexamined Patent Publication No. H02-109051), a technique to apply aphotosensitizer restricting the amount of tetra ester component of1,2-naphthoquinone-2-diazide-5 and/or 4-sulfonic acid ester ofparticular polyhydroxy compounds (Japanese Unexamined Patent PublicationNo. H09-15853), a technique to apply an admixture as a photosensitizerof 1,2-naphthoquinone-2-diazide-5-sulfonic acid ester and1,2-naphthoquinone-2-diazide-4-sulfonic acid ester of2,3,4,4′-tetrahydroxybezophenone at the particular mixing ratio havebeen being proposed. However in the prior art so far proposed, there areproblems in view point of resolution and pattern form where the tailingoccurred and it is desired to provide a radiation sensitive resincomposition having high resolution and good pattern shape which can beapplied for i-line light source exposure and the patter forming methodusing it.

Under the circumstances described above, an object of the presentinvention is to provide a radiation sensitive resin composition fori-line light exposure having high resolution and being able to form agood pattern without tailing etc. and a pattern forming method using it.

DISCLOSURE OF THE INVENTION

As a result of eager study and examination, the present inventors foundthat in pattern forming method using i-line light exposure source aradiation sensitive resin composition comprising an alkali-soluble resinand a quinonediazide group-containing photosensitizer wherein thealkali-soluble resin is a mixture of a novolak resin and one or moreresins selected from (i) polyacrylate, (ii) polymethacrylate, (iii) apolystyrene derivative, and (iv) a copolymer consisting of two or moremonomer units selected from acrylate, methacrylate and a styrenederivative can attain the above object and reached to the presentinvention.

It means the present invention relates to a pattern forming method whichis characterized in that in pattern forming method using i-line lightexposure source a radiation sensitive resin composition comprises analkali-soluble resin and a quinonediazide group-containingphotosensitizer wherein the alkali-soluble resin is a mixture of anovolak resin and one or more resins selected from (i) polyacrylate,(ii) polymethacrylate, (iii) a polystyrene derivative, and (iv) acopolymer consisting of two or more monomer units selected fromacrylate, methacrylate and styrene derivatives.

Further the present invention relates to a radiation sensitive resincomposition for i-line light exposure which is characterized in that aradiation sensitive resin composition comprises an alkali-soluble resinand a quinonediazide group-containing photosensitizer wherein thealkali-soluble resin is a mixture of a novolak resin and one or moreresins selected from (i) polyacrylate, (ii) polymethacrylate, (iii) apolystyrene derivative, and (iv) a copolymer consisting of two or moremonomer units selected from acrylate, methacrylate and styrenederivatives.

Hereinafter, the present invention will be described below further inmore detail.

In the pattern forming method of the present invention i-line is usedfor light exposure source and as a radiation sensitive resin compositionan alkali-soluble resin and a quinonediazide group-containingphotosensitizer wherein the alkali-soluble resin is a mixture of anovolak resin and one or more resins selected from (i) polyacrylate,(ii) polymethacrylate, (iii) a polystyrene derivative, and (iv) acopolymer consisting of two or more monomer units selected fromacrylate, methacrylate and styrene derivatives is used. The lightexposure amount upon exposing i-line using the radiation sensitive resincomposition of the present invention can be varied depending on theconstitution of the radiation sensitive resin composition, howeveroptimal exposure amount forming a pattern without tailing and beingpractically applied is 50 to 500 mJ/cm². When applied for FPD itpreferably applied with 50 to 200 mJ/cm².

A novolak resin preferably used in a radiation sensitive resincomposition for i-line light exposure of the present invention may bethe novolak resin used in the radiation sensitive resin composition sofar known comprising alkali-soluble resin and photosensitizer containingquinonediazide groups and is not limited particularly. A novolak resinpreferably used in the present invention is obtained by polycondensationbetween a various kind of phenol species, singly or a mixture thereofand aldehyde such as formalin.

As the phenols to be used for preparing the novolak resin, there may beillustrated, for example, phenol, p-cresol, m-cresol, o-cresol,2,3-dimethylphenol, 2,4-dimethylphenol, 2,5-dimethylphenol,2,6-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol,2,3,4-trimethylphenol, 2,3,5-trimethylphenol, 3,4,5-trimethylphenol,2,4,5-trimethylphenol, methylene-bisphenol, methylene-bis-p-cresol,resorcinol, catechol, 2-methylresorcinol, 4-methylresorcinol,o-chlorophenol, m-chlorophenol, p-chlorophenol, 2,3-dichlorophenol,m-methoxyphenol, p-methoxyphenol, p-butoxyphenol, o-ethylphenol,m-ethylphenol, p-ethylphenol, 2,3-diethylphenol, 2,5-diethylphenol,p-isopropylphenol, α-naphthol, β-naphthol, and the like. These are usedindependently or as a mixture of two or more thereof.

As the aldehydes, there may be illustrated paraformaldehyde,acetaldehyde, benzaldehyde, hydroxybenzaldehyde, chloroacetaldehyde,etc. as well as formalin. These are used singly or as a mixture of twoor more thereof.

The weight average molecular weight of the novolak resin used in theradiation sensitive resin composition of the present invention, asdetermined using polystyrene standards, is preferably 2,000 to 50,000,more preferably 3,000 to 40,000.

On the other side as monomers constituting polyacrylate (i),polymethacrylate (ii), polystyrene derivatives (iii), a copolymercomprising two or more monomer units selected from the group of acrylicester, methacrylic ester and styrene derivatives (iv), below illustratedacrylic esters, methacrylic esters and styrene derivatives arepreferably raised.

Acrylic Ester:

Methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate,n-hexyl acrylate, isopropyl acrylate, isobutyl acrylate, t-butylacrylate, cyclohexyl acrylate, benzyl acrylate, 2-chloroethyl acrylate,methyl-α-chloroacrylate, phenyl α-bromoacrylate etc.

Methacrylic Ester

Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butylmethacrylate, n-hexyl methacrylate, isopropyl methacrylate, isobutylmethacrylate, t-butyl methacrylate, cyclohexyl methacrylate, benzylmethacrylate, phenyl methacrylate, 1-phenylethyl methacrylate,2-phenylethyl methacrylate, furfuryl methacrylate, diphenylmethylmethacrylate, pentachlorophenyl methacrylate, naphthyl methacrylate,iso-boronyl methacrylate, benzyl methacrylate, etc.

Styrene Derivatives

4-fluorostyrene, 2,5-difluorostyrene, 2,4-difluorostyrene,p-isopropylstyrene, styrene, o-chlorostyrene, 4-acetylstyrene,4-benzoylstyrene, 4-bromostyrene, 4-butoxycarbonylstyrene,4-butoxymethylstyrene, 4-butylstyrene, 4-ethylstyrene, 4-hexylstyrene,4-methoxystyrene, 4-methylstyrene, 2,4-dimethylstyrene,2,5-dimethylstyrene, 2,4,5-trimethylstyrene, 4-phenylstyrene,4-propoxystyrene, etc.

Further an organic acid monomer can be used as a copolymer component forthe above described each polymer, if necessary. The preferable organicacid monomer can be illustrated below.

Organic Acid Monomer

Acrylic acid, methacrylic acid, itaconic acid, maleic anhydride,2-acryloyl hydrogenphthalate, 2-acryloyloxypropyl hydrogenphthalate,etc.

When using an organic acid monomer as a copolymer component, acrylicester, methacrylic ester and styrene derivative part in the copolymersshow alkaline dissolution inhibition effect, whereas organic acidmonomer part shows alkaline dissolution promotion effect. Thereforedepending on the organic acid monomer content, it would be possible tobalance dissolution inhibition effect and dissolution improvement in thelight exposure area of the radiation sensitive resin composition to adeveloper.

Besides the weight average molecular weight of these polyacrylates,polymethacrylates, polystyrene derivatives or copolymers comprising twoor more of monomer unit selected from the group consisting of acrylicesters, methacrylic esters, and styrene derivatives is preferably 2,000to 80,000 as determined using polystyrene standards and is morepreferably 5,000 to 40,000. The content of these polyacrylates,polymethacrylates, polystyrene derivatives or copolymers comprising twoor more of monomer unit selected from the group consisting of acrylicesters, methacrylic esters, and styrene derivatives is preferably 0.1 to10.0 parts by weight relative to 100 parts by weight of novolak resinand more preferably 0.5 to 5.0 parts by weight.

As a photosensitizer containing quinonediazide groups used in aradiation sensitive resin composition for i-line light exposure of thepresent invention, any publicly known photosensitizer containingquinonediazide groups can be used and particularly one obtained by thereaction between quinonediazide-sulfonic acid halide such asnaphthoquinonediazide-sulfonic acid chloride orbenzoquinonediazide-sulfonic acid chloride and low or high molecularweight compounds containing functional groups which can be condensedwith these acid halide is preferred. As functional groups which can becondensed with these acid halide, hydroxyl group or amino group can beexemplified and as low molecular compounds containing hydroxyl groupsfor example, hydroquinone, resorcin, 2,4-dihydroxybenzophenone,2,3,4-trihydroxybenzophenone, 2,4,6-trihydroxybenzophenone,2,4,4′-trihydroxybenzophenone, 2,3,4,4′-tetrahydroxybenzophenone,2,2′,4,4′-tetrahydroxybenzophenone, 2,2′,3,4,6′-pentahydroxybenzophenoneetc. Examples of the high molecular compound containing hydroxyl groupinclude novolak resin and polyhydroxystyrene etc.

The content of a photosensitizer containing quinonediazide groups of thepresent invention is preferred to be 10 to 30 parts by weight, morepreferably 15 to 25 parts by weight relative to 100 parts by weight ofresin component in the radiation sensitive resin composition. In thecase of less than 10 parts by weight the film remaining rate tends todecrease or the process margin such as development time dependency tendsto be deteriorated drastically. In the case of exceeding 30 parts byweight, it could cause a practical problem due to too low sensitivity orcausing the precipitation of photosensitizer.

In the present invention, it is further preferred to incorporate the lowmolecular compounds having the phenolic hydroxy group(s) represented bythe general formula (I) below into the radiation sensitive resincomposition.

wherein R₁, R₂, R₃, R₄, R₅, R₆ and R₇ independently represent H, a C₁-C₄alkyl group, a C₁-C₄ alkoxyl group, a cyclohexyl group, or a grouprepresented by the formula:

wherein R₈ represents H, a C₁-C₄ alkyl group, a C₁-C₄ alkoxyl group or acyclohexyl group; m and n each are 0, 1 or 2; a, b, c, d, e, f, g and hare integers of 0 or 1 to 5 satisfying a +b≦5, c+d≦5, e+f≦5, and g+h≦5;and i is 0, 1 or 2.

The low molecular compounds having the phenolic hydroxy group(s)represented by the general formula (I) is preferably used to control adissolution rate usually as a dissolution promoter in the radiationsensitive resin composition of the present invention or to improve thesensitivity of the radiation sensitive resin composition or to controlthe sensitivity.

As the low-molecular compound having phenolic hydroxyl group or groupsrepresented by the above general formula (I), there are illustrated, forexample, o-cresol, m-cresol, p-cresol, 2,4-xylenol, 2,5-xylenol,2,6-xylenol, bisphenol A, B, C, E, F, or G,4,4′,4″-methylidinetrisphenol,2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenol,4,4′-[1-[4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene]bis-phenol,4,4′,4″-ethylidinetrisphenol,4-[bis(4-hydroxyphenyl)methyl]-2-ethoxyphenol,4,4′-[(2-hydroxyphenyl)methylene]bis[2,3-dimethylphenol],4,4′-[(3-hydroxyphenyl)methylene]bis[2,6-dimethylphenol],4,4′-[(4-hydroxyphenyl)methylene]bis[2,6-dimethylphenol],2,2′-[(2-hydroxyphenyl)methylene]bis[3,5-dimethylphenol],2,2′-[(4-hydroxyphenyl)methylene]bis[3,5-dimethylphenol],4,4′-[(3,4-dihydroxyphenyl)methylene]bis[2,3,6-trimethylphenol],4-[bis(3-cyclohexyl-4-hydroxy-6-methylphenyl)methyl]-1,2-benzenediol,4,6-bis[(3,5-dimethyl-4-hydroxyphenyl)methyl]-1,2,3-benzenetriol,4,4′-[(2-hydroxyphenyl)methylene]bis[3-methylphenol],4,4′,4″-(3-methyl-1-propanyl-3-ylidine)trisphenol,4,4′,4″,4′″-(1,4-phenylenedimethylidine)tetrakisphenol,2,4,6-tris[(3,5-dimethyl-4-hydroxyphenyl)methyl]-1,3-benzenediol,2,4,6-tris[(3,5-dimethyl-2-hydroxyphenyl)methyl]-1,3-benzenediol,4,4′-[1-[4-[1-[4-hydroxy-3,5-bis[(hydroxy-3-methylphenyl]methyl]phenyl]-1-methylethyl]phenyl]ethylidene]bis[2,6-bis(hydroxy-3-methylphenyl)methyl]phenol,and the like. These low-molecular compounds having phenolic hydroxylgroup or groups are used in an amount of usually 1 to 20 parts byweight, preferably 3 to 15 parts by weight relative to 100 parts byweight of the novolak resin.

The fluorescent material can be added into the radiation sensitive resincomposition of the present invention. The fluorescent material to beused into the radiation sensitive resin composition of the presentinvention include naphthalene and naphthalene derivatives, e.g.,1-hydroxynaphthalene, 1-methylnaphthalene, 2,3-dimethylnaphthalene,1-aminonaphthalene, 2-fluoronaphthalene, 2-chloronaphthalene,1,7-diphenylnaphthalene, and the like; anthracene and anthracenederivatives, e.g., 9-methylanthracene, 9,10-dimethylanthracene,9-cyanoanthracene, 1-aminoanthracene, 9-phenylanthracene,9,10-diphenylanthracene, 9,10-dichloroanthracene,9,10-dinaphthylanthracene, 9-vinylanthracene,9-(p-vinylphenyl)-10-phenylanthracene, and the like; phenanthrene andphenanthrene derivatives, e.g., 3,4′-benzophenanthrene,2-phenylphenanthrene, and the like; pyrene and pyrene derivatives, e.g.,1,3,6,8-tetraphenylpyrene, bipyrenyl, o-phenylenepyrene, and the like;perylene and perylene derivatives, e.g., benzoperylene and the like;fluorene and fluorene derivatives, e.g., 1-methylfluorene,1,2-benzofluorene, and the like; carbazole and carbazole derivatives,e.g., N-methylcarbazole, N-methylbenzocarbazole, N-phenylcarbazole,N-vinylcarbazole, and the like; biphenyl and biphenyl derivatives, e.g.,4-methylphenylbiphenyl, 3,3′-dimethylbiphenyl, 4-methoxybiphenyl,4,4′-dimethoxybiphenyl, 4,4′-dihydroxybiphenyl, 4-benzylbiphenyl,4-vinylbiphenyl, octamethylbiphenyl and the like; p-terphenyl andp-terphenyl derivatives, e.g., 4-methylterphenyl, 2-methyl-p-terphenyl,3,3″-dimethylterphenyl, 4-(3,3-dimethylbutoxy)-p-terphenyl,2,2′-methylene-p-terphenyl, and the like; p-quaterphenyl andp-quaterphenyl derivatives, e.g., 3,3′″-dimethyl-p-quaterphenyl,tetramethyl-p-quaterphenyl, 4-(3-ethylbutoxy) -p-quaterphenyl, and thelike; indole and indole derivatives, e.g., 2-phenylindole,1-methyl-2-phenylindole, 1-N-butyl-2-biphenylindole, 1,2-diphenylindole,1-biphenyl-2-indole, and the like; acridine and derivatives thereof,naphthacene and derivatives thereof; rublene and derivatives thereof;chrysene and derivatives thereof; and so on. It is preferable that thesefluorescent materials are selected by taking into account the absorptionwavelength range of the photosensitizer to be combined and then thesefluorescent materials may be used singly or in a combination of two ormore. The amount of the fluorescent material to be incorporated is0.0001 to 1.0 parts by weight relative to 100 parts by weight of thephotosensitizer, preferably 0.0005 to 0.5 parts by weight. Theincorporation of these fluorescent materials can improve thesensitivity.

The solvents for dissolving an alkali soluble resin, a photosensitizerand the dissolution promoter represented by the general formula (I) ofthe present invention include ethylene glycol monoalkyl ethers such asethylene glycol monomethyl ether and ethylene glycol monoethyl ether;ethylene glycol monoalkyl ether acetates such as ethylene glycolmonomethyl ether acetate and ethylene glycol monoethyl ether acetate;propylene glycol monoalkyl ethers such as propylene glycol monomethylether and propylene glycol monoethyl ether; propylene glycol monoalkylether acetates such as propylene glycol monomethyl ether acetate andpropylene glycol monoethyl ether acetate; lactates such as methyllactate and ethyl lactate; aromatic hydrocarbons such as toluene andxylene; ketones such as methyl ethyl ketone, 2-heptanone, andcyclohexanone; amides such as N,N-dimethylacetamide andN-methylpyrrolidone; lactones such as γ-butyrolactone; and so on. Thesesolvents are used singly or in a combination of two or more thereof.

Further, dyestuffs, adhesive aids, surfactants etc. may be incorporatedas necessary into the radiation sensitive resin composition of thepresent invention. The dyestuffs include e.g. Methyl Violet, CrystalViolet, Malachite Green etc.; the adhesive aids include e.g. alkylimidazoline, butyric acid, alkyl acid, polyhydroxystyrene,polyvinylmethyl ether, t-butyl novolak, epoxy silane, epoxy polymer,silane etc.; and the surfactants include e.g. nonionic surfactants suchas polyglycols and derivatives thereof, that is, polypropylene glycol orpolyoxyethylene lauryl ether, fluorine-containing surfactants such asFluorad (trade name; manufactured by Sumitomo 3M Ltd.), Megafac (tradename; manufactured by Dai-Nippon Ink & Chemicals, Inc.), Sulflon (tradename; manufactured by Asahi Glass Co., Ltd.) or organosiloxanesurfactants such as KP341 (trade name; Shin-Etsu Chemical Co., Ltd.).

By the way the resist sensitivity has a property which cannot bedetermined in one to one relation since the resist sensitivity issignificantly sensitive to a process condition and the value ofsensitivity can be determined only when its process condition isdetermined as some condition like uncertainty principle. The optimalradiation exposure quantity described in the present invention is thevalues measured in the below described process condition. First as asubstrate is used 4 inch-silicon wafer or glass wafer. Coating conditionis to coat resist by spin coating method with a rotation number whichgives 1.5 microns resist film thickness when prebaked at 100° C. for 90seconds. And then an exposure to light is conducted by using the stepperproduced by Hitachi Co., Ltd. (light source i-line, wavelength 365 nm,NA=0.50) as a light-exposure apparatus. A development condition afterexposure to light is to use 2.38 weight % TMAH (tetramethylammoniumhydroxide) as a developer and to develop by puddle system at 23° C. for60 seconds, after that the substrate is rinsed with pure water for 60seconds and to dried-up. The above is the process condition whenmeasuring an optimal light-exposure quantity described in the presentinvention and an optimal light-exposure quantity will change when thisprocess condition is altered.

BEST MODE FOR PRACTICING THE INVENTION

The present invention will now be described more specifically byreference to Examples which, however, are not to be construed to limitthe present invention in any way.

EXAMPLE 1

To 100 parts by weight of a novolak resin having weight averagemolecular weight, 8,000 as determined using polystyrene standards wereadded 2 parts by weight of poly(methyl methacrylate-co-n-butylmethacrylate), 21 parts by weight of an esterification product between2,3,4,4′-tetrahydroxy-benzophenone and1,2-naphthoquinonediazide-5-sulfonyl chloride having averageesterification rate of 75%, 5 parts by weight of4,4′-[1-[4-[1-(4-hydroxyphenyl)-1-methyethyl]phenyl]ethylidene]bisphenolwere dissolved in 390 parts by weight of propylene glycol monomethylether acetate, after adding thereto 300 ppm of a fluorine-containingsurfactant, Megafac (manufactured by Dai-Nippon Ink & Chemicals, Inc.)to the total solid content, the solution was stirred and filteredthrough a 0.2-μm filter to prepare a radiation sensitive resincomposition of the present invention. This composition was spin-coatedon a 4-inch silicon wafer and a 4-inch glass wafer, and baked on a hotplate at 100° C. for 90 seconds to obtain a 1.5-μm thick resist layer.These resist layers were exposed by an i-line stepper (NA=0.5) made byHitachi Co., Ltd. and developed in a 2.38 weight-% aqueous solution ofTMAH at 23° C. for 60 seconds. After that an optimal light-exposurequantity, a limit resolution and a pattern form by scanning electronicmicroscope were respectively observed and then the optimallight-exposure quantities were 80 mJ/cm² for 4-inch silicon wafer, 72mJ/cm² for 4-inch glass wafer, the limit resolutions were both 0.5microns and the pattern shapes were both rectangular which was good.

EXAMPLE 2

The same manner was taken as Example 1 apart from using a mixture (50:50mixing ratio) of an esterification product between2,3,4,4′-tetrahydroxy-benzophenone and1,2-naphthoquinonediazide-5-sulfonyl chloride having averageesterification rate of 87.5% and an esterification product between2,3,4,4′-tetrahydroxy-benzophenone and1,2-naphthoquinonediazide-5-sulfonyl chloride having averageesterification rate of 75% and the optimal light-exposure quantitieswere 85 mJ/cm² for 4-inch silicon wafer, 77 mJ/cm² for 4-inch glasswafer, the limit resolutions were both 0.5 microns and the patternshapes were both rectangular which was good.

EXAMPLE 3

The same manner was taken apart from anthracene, 2.1×10⁻⁵ parts byweight (0.0001 parts by weight to the photosensitizer) being added as afluorescent material and the optimal light-exposure quantities were 75mJ/cm² for 4-inch silicon wafer, 68 mJ/cm2 for 4-inch glass wafer, thelimit resolutions were both 0.5 microns and pattern shapes were bothrectangular which was good.

EXAMPLE 4

The same manner was taken apart from anthracene, 1.05×10⁻³ parts byweight (0.005 parts by weight to the photosensitizer) being added as afluorescent material and the optimal light-exposure quantities were 71mJ/cm² for 4-inch silicon wafer, 64 mJ/cm2 for 4-inch glass wafer, thelimit resolutions were both 0.5 microns and the pattern shapes were bothrectangular which was good.

EXAMPLE 5

The same manner was taken apart from anthracene, 2.1×10⁻² parts byweight (0.1 parts by weight to the photosensitizer) being added as afluorescent material and the optimal light-exposure quantities were 74mJ/cm² for 4-inch silicon wafer, 67 mJ/cm2 for 4-inch glass wafer, thelimit resolutions were both 0.5 microns and the pattern shapes were bothrectangular which was good.

Comparative Example 1

The same manner was taken as Example 1 apart from using 25 parts byweight of an esterification product between2,3,4,4′-tetrahydroxy-benzophenone and1,2-naphthoquinonediazide-5-sulfonyl chloride having averageesterification rate of 75% and without using poly(methylmethacrylate-co-n-butyl methacrylate) and the optimal light-exposurequantities were 80 mJ/cm² for 4-inch silicon wafer, 72 mJ/cm2 for 4-inchglass wafer, the limit resolutions were both 0.75 microns and thepattern shapes showed both tailing which was worse pattern inverticality compared with those of Examples.

Effectiveness of Invention

As mentioned above the pattern with high resolution and good patternshape by i-line light-exposure can be formed by the present invention.

Industrial Applicability

The radiation sensitive resin composition of the present invention canbe properly used for manufacturing semiconductor devices, flat paneldisplay (FPD), etc. as a photoresist material.

What is claimed is:
 1. A method of forming a pattern with i-line as anexposure light source by use of a radiation sensitive resin compositioncomprising an alkali-soluble resin and a quinonediazide group-containingphotosensitizer wherein the alkali-soluble resin is a mixture of anovolak resin and one or more resins selected from (i) polyacrylatepolymerized with an acrylic ester monomer (ii) polymethacrylatepolymerized with a methacrylic ester monomer (iii) a polystyrenederivative, and (iv) a copolymer consisting of two or more monomer unitsselected from acrylic ester, methacrylic ester, a styrene derivative andan organic acid monomer; wherein said acrylic ester is a monomer unitselected from a group consisting of methyl acrylate, ethyl acrylate,n-propyl acrylate, n-butyl acrylate, n-hexyl acrylate, isopropylacrylate, isobutyl acrylate, t-butyl acrylate, cyclohexyl acrylate,benzyl acrylate, 2-chloroethyl acrylate, methyl-α-chloroacrylate, andphenyl α-bromoacrylate; and, further wherein methacrylic ester is amonomer unit selected from a group consisting of methyl methacrylate,ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, n-hexylmethacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butylmethacrylate, cyclohexyl methacrylate, benzyl methacrylate, phenylmethacrylate, 1-phenylethyl methacrylate, 2-phenylethyl methacrylate,furfuryl methacrylate, diphenylmethyl methacrylate, pentachlorophenylmethacrylate, naphthyl methacrylate, iso-boronyl methacrylate, andbenzyl methacrylate.
 2. A radiation sensitiye resin composition fori-line light exposure comprising an alkali-soluble resin and aquinonedlazide group-containing photosensitizer, wherein thealkali-soluble resin is a mixture of a novolak resin and one or moreresins selected from (i) polyacrylate polymerized with an acrylic estermonomer (ii) polymethacrylate polymerized with a methacrylic estermonomer (iii) a polystyrene derivative, and (iv) a copolymer consistingof two or more monomer units selected from acrylic ester, methacrylicester, a styrene derivative and an organic acid monomer; wherein saidacrylic ester is a monomer unit selected from a group consisting ofmethyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate,n-hexyl acrylate, isopropyl acrylate, isobutyl acrylate, t-butylacrylate, cyclohexyl acrylate, benzyl acrylate, 2-chloroethyl acrylate,methyl-α-chloroacrylate, and phenyl α-bromoacrylate; and, furtherwherein methacrylic ester is a monomer unit selected from a groupconsisting of methyl methacrylate, ethyl methacrylate, n-propylmethacrylate, n-butyl methacrylate, n-hexyl methacrylate, isopropylmethacrylate, isobutyl methacrylate, t-butyl methacrylate, cyclohexylmethacrylate, benzyl methacrylate, phenyl methacrylate, 1-phenylethylmethacrylate, 2-phenylethyl methacrylate, furfuryl methacrylate,diphenylmethyl methacrylate, pentachlorophenyl methacrylate, naphthylmethacrylate, iso-boronyl methacrylate, and benzyl methacrylate.
 3. Theradiation sensitive resin composition for i-line light exposureaccording to claim 2, wherein the quinonediazide group-containingphotosensitizer is an esterified product of tetrahydroxybenzophenone and1,2-naphthoquinonediazide-sulfonic acid.
 4. The radiation sensitiveresin composition for i-line light exposure according to claim 2,wherein the quinonediazide group-containing photosensitizer is a mixtureof esterified products of tetrahydroxybenzophenone and1,2-naphthoquinonediazide-sulfonic acid.
 5. The radiation sensitiveresin composition for i-line light exposure according to claim 2,wherein a fluorescent material is incorporated in an amount of 0.0001 to1.0 part by weight relative to 100 parts by weight of the quinonediazidegroup-containing photosensitizer.
 6. The radiation sensitive resincomposition for i-line light exposure according to claim 3, wherein thequinonediazide group-containing photosensitizer is a mixture ofesterified products of tetrahydroxybenzophenone and1,2-naphthoquinonediazide-sulfonic acid.
 7. The radiation sensitiveresin composition for i-line light exposure according to claim 3,wherein a fluorescent material is incorporated in an amount of 0.0001 to1.0 part by weight relative to 100 parts by weight of the quinonediazidegroup-containing photosensitizer.
 8. The radiation sensitive resincomposition for i-line light exposure according to claim 4, wherein afluorescent material is incorporated in an amount of 0.0001 to 1.0 partby weight relative to 100 parts by weight of the quinonediazidegroup-containing photosensitizer.
 9. The radiation sensitive resincomposition for i-line light exposure according to claim 2, where theorganic acid monomer is selected from acrylic acid, methacrylic acid,itaconic acid, maleic anhydride, 2-acryoyl hydrogenphthalate and2-acryloyloxypropyl hydrogenphthalate.
 10. The method of forming apattern for i-line light exposure according to claim 1, where theorganic acid monomer is selected from acrylic acid, methacrylic acid,itaconic acid, maleic anhydride, 2-acryoyl hydrogenphthalate and2-acryloyloxypropyl hydrogenphthalate.
 11. The radiation sensitive resincomposition for i-line light exposure according to claim 2, where thestyrene derivative is selected from 4-fluorostyrene,2,5-difluorostyrene, 2,4-difluorostyrene, p-isopropylstyrene, styrene,o-chlorostyrene, 4-acetylstyrene, 4-benzoylstyrene, 4-bromostyrene,4-butoxycarbonylstyrene, 4-butoxymethylstyrene, 4-butylstyrene,4-ethylstyrene, 4-hexylstyrene, 4-methoxystyrene, 4-methylstyrene,2,4-dimethylstyrene, 2,5-dimethylstyrene, 2,4,5-trimethylstyrene,4-phenylstyrene, and 4-propoxystyrene.
 12. The method of forming apattern for i-line light exposure according to claim 1, where thestyrene derivative is selected from 4-fluorostyrene,2,5-difluorostyrene, 2,4-difluorostyrene, p-isopropylstyrene, styrene,o-chlorostyrene, 4-acetylstyrene, 4-benzoylstyrene, 4-bromostyrene,4-butoxycarbonylstyrene, 4-butoxymethylstyrene, 4-butylstyrene,4-ethylstyrene, 4-hexylstyrene, 4-methoxystyrene, 4-methylstyrene,2,4-dimethylstyrene, 2,5-dimethylstyrene, 2,4,5-trimethylstyrene,4-phenylstyrene, and 4-propoxystyrene.
 13. The method of forming apattern for i-line light exposure according to claim 1, wherein theradiation sensitive composition further comprises a fluorescent materialin an amount of 0.0001 to 1.0 part by weight relative to 100 parts byweight of the quinonediazide group-containing photosensitizer.
 14. Themethod of forming a pattern for i-line light exposure according to claim1, comprising the steps of forming a coating of the radiation sensitivecomposition on a substrate, image-wise exposing the coating, anddeveloping the coating.